1. Field of the Invention
This invention relates to circular sawing machine and has specific reference to improved means for guiding the carriage of a machine for sawing plates from beneath, the frame of this machine comprising essentially box-section side supporting members forming between them a sawing channel and having guide rails secured thereto.
2. The Prior Art
Most plate sawing machines are relatively long and their carriage or carriages travel on guide rails incorporated in and supported by the frame. Now the sawing precision is frequently subordinate to the care exerted when positioning the guide rails. Besides, these guide rails must compulsorily have well-defined characteristics such as a reliable protection against shocks and the ingress of shavings and chips, dust and other undesired foreign substances, while preserving an easy access to facilitate any necessary adjustment. To obtain a maximum stability of the carriage during its movements, the guide rail spacing should be as broad as possible as a function of the width of the sawing machine whereas the vertical position of these guide rails should be relatively low in relation to the saw blade.
Various guiding systems have already been proposed in the art. One known device comprises modular component elements in the form of frames of which the number is subordinate to the length of the sawing machine. These modular elements adapted to be assembled horizontally comprise a closed-type frame bearing on the floor through relatively close-spaced legs. These modular elements comprise at their top a slot permitting the passage of the saw blade. The carriage guide rails are fixed to the inner walls of the modular elements. There are several ways of positioning said guide rails. Thus, the two guide rails are rigidly secured either to the upper inner wall, or to the lower inner wall, or to the inner side walls, or alternately one of the guide rail is rigidly secured to the upper inner wall and the other guide rail is secured to the lower inner wall or to one of the inner side walls.
Another guiding system for the carriage of a sawing machine comprising a chassis with carrier beams which is as long as the sawing machine itself is also known. This chassis comprises on the one hand two parallel box-section side members of square or rectangular cross-section, disposed on either side of the sawing line, and on the other hand a transverse table interconnecting the two carrier beams and provided with a longitudinal slot through which the saw blade can protrude. One of the vertical walls of the carrier beams comprises a downward extension constituting a supporting member. The guide rails are secured either to the bottom face of the transverse table, or to the inner face of the supporting member, but a different combinating of these positions may also be contemplated.
However, in these known arrangements the guide rails are located in close vicinity of the sawing channel. Therefore, the guide rails are not protected against the detrimental effect of shawings, chips and dust. Moreover, when the sawing machine comprises a chassis with supporting beams, the guide rails are disposed between these beams and are therefore difficult of access.